Image processing module, data processing module and methods for using the same

ABSTRACT

An image processing module substantially matches the representation of a display with the expectation of image data. The image processing module comprises a storage unit, a control unit, and an image processing unit. The storage unit stores calibration information with calibration values each corresponding to a physical area on the display. The control unit receives timing data and mode data to accordingly direct the storage unit to output corresponding calibration value. An image processing unit is controlled by the control unit to calibrate the image data according to the corresponding calibration value and output calibrated image data.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a data processing method and a data processingapparatus, and in particular to an image data processing method and animage data processing apparatus.

2. Description of the Related Art

Different pixels (or lines) of a display apparatus may have producedifferent color performance for the same data for reasons such asmanufacturing or processing deviation on the different pixels. Forexample, the geographical dependence shown in FIG. 1(a) is generallyobtained even though the ideal result of FIG. 1(b) is preferred.

FIG. 3 shows a conventional control scheme for a display apparatus,having an analog-to-digital converter (ADC) 100, an image scaling module200, an image processing module 300 and a display module 400. ADC 100converts image data from analog form to digital form. Based uponreceived digital control data, image scaling module 200 processes thedigitalized image data, scaling the image data. After scaling, imageprocessing module 300 performs image correction or calibrationcomprising, for example, brightness, contract, sharpness, or gammavalues. Finally, display module 400 displays images according to theimage data from image processing module 300.

Conventional image processing modules substantially process data byframe, such that conventional calibration only shifts the line ofgeographical dependence in parallel, without straightening it, as shownin FIG. 1(c). Therefore, the conventional image processing modulescannot calibrate specific locations inside a frame if calibration of thespecific locations is desired. Further, TFT LCD displays, due tocharacteristics of liquid crystal, must be periodically inverted. FIG.2(c) shows a preferred relationship between input and output signals,wherein one line refers to a non-inversion mode and the other refers toan inversion mode. The lines in FIG. 2(cl ) are straight and angledabout 45° from a horizontal line, such that the input and output datahave the same value in the non-inversion mode and said data arecomplimentary in inversion mode. These two straight lines also representthe linear relationship between the input and output data irrespectiveof mode. Due to device deviation and mismatch, output data may differfrom input data, with the line for inversion mode deviating from amirror image of the line for non-inversion mode, as shown in FIG. 2(a).Conventional technology employs one signal formula to calibrate theoutput data in both non-inversion and inversion modes. One of thepossible results of the conventional technology is shown in FIG. 2(b),where, even the line for non-inversion mode is calibrated to becomestraight, the line for the inversion mode is still a curve, representingan unwanted, non-linear relationship between the input and outputsignals. Thus, the conventional technology cannot create two straightlines as ideally expected in FIG. 2(c), such that conventional imageprocessing modules fail to provide good images quality.

BRIEF SUMMARY OF THE INVENTION

One embodiment of the present invention provides an image processingmodule comprising a storage unit, a control unit, and an imageprocessing unit. The storage unit stores calibration information withcalibration values each corresponding to a physical area on a display.The control unit receives timing data and mode data to accordinglydirect the storage unit to output a corresponding calibration value. Theimage processing unit is controlled by the control unit to calibrateimage data according to the corresponding calibration value and outputcalibrated image data.

One embodiment of the present invention provides a data processingmodule controlling an apparatus that has operation units. The dataprocessing module comprising a storage unit, a control unit, and aprocessing unit. The storage unit stores calibration information withcalibration values, each respectively corresponding to one operationunit. A control unit receives timing data and mode data to accordinglydirect the storage unit to output a corresponding calibration value. Theprocessing unit is controlled by the control unit to calibrate controldata according to the corresponding calibration value and outputcalibrated control data, such that the representation of the apparatusunder the control of the data processing module substantially matchesthe expectation of the control data.

One embodiment of the present invention provides an image dataprocessing method. Timing data and mode data are first received. Acorresponding calibration value is output from a storage unit accordingto the timing data and the mode data. Image data is calibrated accordingto the corresponding calibration value to output calibrated image data.The corresponding calibration value corresponds to a spatial location towhich the timing data refers.

A detailed description is given in the following embodiments withreference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The invention can be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1(a) shows line-dependence of the performance of a liquid crystaldisplay;

FIG. 1(b) shows expected line-independence of performance of a liquidcrystal display;

FIG. 1(c) shows a conventional calibration method shifting only thecurve of a line-dependence;

FIG. 1(d) shows line-independence performed according to an imageprocessing module of the invention;

FIG. 2(a) shows a possible relationship between input data and outputdata of a liquid crystal under inversion or non-inversion;

FIG. 2(b) shows a calibrated relationship between input data and outputdata after processing by conventional calibration;

FIG. 2(c) shows a preferred relationship between input data and outputdata of a liquid crystal under inversion or non-inversion;

FIG. 2(d) shows the relationships between input data and output dataprocessed by a calibration method of the invention;

FIG. 3 shows a conventional control scheme for a display apparatus;

FIG. 4 shows operation of an image processing module according to anembodiment of the invention;

FIG. 5 exemplifies the calibration information stored in a storage unit;and

FIG. 6 lists the possible and selectable calibration modes according tothe invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best-contemplated mode of carryingout the invention. This description is made for the purpose ofillustrating the general principles of the invention and should not betaken in a limiting sense. The scope of the invention is best determinedby reference to the appended claims.

FIG. 4 shows operation of an image processing module according to oneembodiment of the invention. The image processing module 300 comprisesan image processing unit 310, a storage unit 320, a control unit 330,and a selection unit 340. Image processing unit 310 calibrates receiveddigital image data. Storage unit 320 stores calibration information, tocorresponding addresses, including correction or calibration values, asshown in FIG. 5, the values of which may relate to calibration of gamma,brightness, contrast, sharpness, etc. Some of the values stored instorage unit 320 correspond to a physical area on a display. Forexample, each value of brightness calibration in storage unit 320corresponds to a dot, a pixel, a row, a column, or a predeterminedsection of a display. Control unit 330 controls the image processexecuted by image processing unit 310, and allocates memory addresses instorage unit 320 such that corresponding values in storage unit 320 canbe properly output for calibration or correction.

The following details the operation of image processing module 300.Control unit 330 receives timing data (for example, verticalsynchronization, horizontal synchronization, or pixel clock), mode data(shown in FIG. 6 as an example), and calibration information (forexample, calibrations of gamma, brightness, contrast, or sharpness).Control unit 330 then stores the calibration information tocorresponding addresses in storage unit 320, and values for one type ofcalibration are gathered together. Thereafter, control unit 330 choosesa calibration or correction function(s), corresponding to the mode data.If the mode data indicates mode 14 in FIG. 6, for example, lineinversion gamma calibration and contrast calibration are required.Control unit 330 then controls the values corresponding to the requiredfunction(s) and the timing of the timing data to output to imageprocessing unit 310. Image processing unit 310 accordingly executesimage processing based upon the received digital image data and thevalues from storage unit 320, such that calibrated image data is sent tostorage unit 320 and selection unit 340. If image processing unit 310performs only calibrations other than desired gamma calibration, storageunit 320 can provide gamma calibration. Storage unit 320 checks a gammalookup table stored therein with calibrated image data to accordinglyoutput gamma-calibrated data to selection unit 340. Based upon thecommand of control unit 330, selection unit 340 chooses thegamma-calibrated data from storage unit 320 or the calibrated image datafrom image processing unit 310 for outputting. Selection unit 340 may bea multiplexer.

In embodiments of the invention, calibration information must be firstset. If dot calibration of a liquid crystal display is required,calibration information regarding to each dot on the liquid crystaldisplay must be determined. If a specific dot of the liquid crystaldisplay performs as if having a brightness value of 100 while receivinga signal with a brightness value of 80, the brightness calibration valuefor that specific dot is 0.8(=80/100) when multiplication operation isemployed, minus 20(=80−100) when addition operation is employed, oranother corresponding value when another kind of operation is employed.The brightness calibration value is stored in a section of storage unit320 for brightness calibration to an address corresponding to thespecific dot of the liquid crystal display. Accordingly, calibrationinformation regarding to sharpness, brightness, contract or otherfeatures of each dot can also be stored to corresponding addresses. Inother words, the calibration values in the calibration information havea spatial correspondence with the liquid crystal display. The timingdata assures that the image data of which dots is going to be calibratedby image processing unit 310, such that storage unit 320 outputs thecalibration information in a corresponding address and sends it to imageprocessing unit 310. According to the received calibration information,image processing unit 310 calibrates the image data of the dot. Forexample, if the received calibration information is minus 20 and thecurrent value of the original image data is 80, then image processingunit 310 outputs a calibrated image data with a value of 60 to make thereal performance of a corresponding dot on a liquid crystal display 80.Since the image data of each dot can be calibrated by correspondingcalibration information in a corresponding address of storage unit 320,it is expected that the performance of the liquid crystal display can beidealized as shown in FIG. 1(d).

As described, the liquid crystal in TFT LCD apparatuses must beperiodically inverted. The inversion schemes commonly used in the artinclude dot, pixel, and line inversion. Here, the line inversion is usedas an example. Operation scheme of a line inversion are odd lines of adisplay at one status while even lines at the other with these twostatuses exchanged periodically. For example, in one frame period, oddlines are in non-inversion status when even lines are in inversionstatus, and in the following frame period, odd lines are in inversionstatus when even lines are in non-inversion status. Liquid crystalperforms differently when operated under a different status. Thus, agamma lookup table preferably has two lookup tables: hereinafter, onenamed a gamma even table for inverted lines and the other named a gammaodd table for non-inverted lines. Thus, at one frame for a first lineperiod, storage unit 320 (under the control of control unit 330)provides the values in the gamma even table for the first line, for thesecond line period, provides the values in the gamma odd table for thesecond line, for the third line period, provides the values in the gammaeven table for the third line and so on. At next frame, each line isprovided with other gamma even table, i.e., the gamma odd table thefirst line, the gamma even table the second line, and so on. Thus, theresult in FIG. 2(d) can be achieved. For the line-to-line difference forgamma calibration, only a gamma even table for all inverted lines and agamma odd table for all non-inverted lines might not be enough. Thus, agamma lookup table can also comprise pairs of tables, each paircorresponding to one line on a display and comprising a gamma even tableand a gamma odd table. Furthermore, suitable values for brightness,sharpness, or contract calibration under non-inversion can differslightly from those under inversion. Therefore, the values of thecalibration information regarding to brightness, sharpness, or contractcan correspond not only to a physical area on a display, but also to aninversion type. For example, the calibration of brightness for a linemight have two values: one for inversion and the other fornon-inversion.

One object of the invention is to calibrate or correct image data toprovide a displayed image substantially the same as expected. The imageprocess employed in the invention can thus be utilized at any stage inthe image process flow from the original image data to a display. Inother words, the digital image data input to image processing unit 310may be calibrated image data or not being calibrated image data, and theoutput image data from image processing unit 310 may directly output toa display or output to other image processing for further processing.Furthermore, the gamma calibration provided by storage unit 320 in theembodiments can be omitted and relocated to a previous process stage ora following stage.

In addition to image processing of individual lines or dots, theinvention can further provide image processing to a pixel, a row, acolumn, or a predetermined section on the display.

In practice, storage unit 320 can utilize a conventional storage unitstoring 3 gamma lookup tables for 3 colors (RGB). The storage capacityfor 2 gamma lookup tables can be replaced and stores the calibrationvalues relating to calibration of brightness, contrast, or sharpnesswhile the gamma calibration of 3 colors (RGB) shares the remaining gammalookup table, which occupies one third of the total capacity of thestorage unit. Hence, the invention can be embodied without complicatedhardware modification.

The invention is applicable, but not limited, to applications in imageprocess. One object of the invention is to modify, calibrate, or correctan input data, such that output data can generate an expectedperformance. More especially, the modification, calibration orcorrection is based upon the geographical deviation of a physicalapplication that uses the data, such that the performance for thephysical application has no geographical dependence. For example, theinvention can be embodied by a data processing module for controlling anapparatus. In the data processing module, a storage unit store modecalibration information, which is utilized to calibrate a control datain order to make the representation of the apparatus under the controlof the data processing module substantially match the expectation of thecontrol data. If the apparatus has several operation units, the modecalibration information can have portions respectively corresponding tothe operation units for better calibration or correction.

While the invention has been described by way of examples and in termsof preferred embodiment, it is to be understood that the invention isnot limited to thereto. To the contrary, it is intended to cover variousmodifications and similar arrangements (as would be apparent to thoseskilled in the art). Therefore, the scope of the appended claims shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar arrangements.

1. An image processing module, comprising: a storage unit storingcalibration information, the calibration information includingcalibration values each corresponding to a physical area on a display; acontrol unit receiving timing data and mode data to accordingly directthe storage unit to output a corresponding calibration value; and animage processing unit controlled by the control unit to calibrate imagedata according to the corresponding calibration value and outputcalibrated image data.
 2. The image processing module as claimed inclaim 1, wherein the control unit further receives the calibrationinformation, and stores the calibration information to correspondingaddresses in the storage unit.
 3. The image processing module as claimedin claim 1, wherein the calibration information comprises a gamma lookuptable.
 4. The image processing module as claimed in claim 3, wherein thestorage unit outputs gamma-calibrated image data according to thecalibrated image data.
 5. The image processing module as claimed inclaim 4, further comprising a selection unit receiving the calibratedimage data and the gamma-calibrated image data and selectivelyoutputting one of the calibrated image data and the gamma-calibratedimage data.
 6. The image processing module as claimed in claim 5,wherein the control unit controls the selection of the selection unitbased on the mode data.
 7. The image processing module as claimed inclaim 3, wherein the gamma lookup table occupies one third the space ofthe storage unit.
 8. The image processing module as claimed in claim 1,wherein the physical area on the display is that of a dot, pixel, row,column, or predetermined section on the display.
 9. The image processingmodule as claimed in claim 1, wherein the mode data comprises values ofcontrast, brightness, sharpness, gamma, or a combination thereof. 10.The image processing module as claimed in claim 9, wherein the displayis a liquid crystal display, and the calibration values compriseinversion and non-inversion mode of the liquid crystal for the liquidcrystal display.
 11. The image processing module as claimed in claim 1,wherein the display is a liquid crystal display, and the calibrationvalues comprise inversion and non-inversion mode values of the liquidcrystal for the liquid crystal display
 12. The image processing moduleas claimed in claim 9, wherein the calibration information comprises agamma lookup table including a gamma odd table and a gamma even tableused for gamma calibration during non-inversion and inversion of theliquid crystal, respectively.
 13. A data processing module forcontrolling an apparatus that has operation units, comprising: a storageunit storing calibration information with calibration values, eachrespectively corresponding to one of the operation units; a control unitreceiving timing data and mode data to accordingly direct the storageunit to output a corresponding calibration value; and a processing unitcontrolled by the control unit to calibrate control data according tothe corresponding calibration value and output calibrated control data,such that the representation of the apparatus under the control of thedata processing module substantially matches the expectation of thecontrol data.
 14. The data processing module as claimed in claim 13,wherein the apparatus is a display.
 15. The data processing module asclaimed in claim 14, wherein the calibration information comprises atleast one mode values of contrast, brightness, sharpness, gamma, or acombination thereof.
 16. The data processing module as claimed in claim14, wherein the display is a liquid crystal display, and the calibrationvalues further comprise inversion and non-inversion mode values of theliquid crystal.
 17. The data processing module as claimed in claim 16,wherein the calibration values have a spatial correspondence with theliquid crystal display.
 18. The data processing module as claimed inclaim 17, wherein the spatial correspondence is related to a dot, pixel,row, column, or predetermined section on the liquid crystal display. 19.An image data processing method, comprising: receiving timing data andmode data; according to the timing data and the mode data, directing astorage unit to output a corresponding calibration value; andcalibrating image data according to the corresponding calibration valueand outputting a calibrated image data, wherein the correspondingcalibration value corresponds to a spatial location to which the timingdata refers.
 20. The image data processing method as claimed in claim19, wherein the storage unit stores calibration information, and thecalibration information has calibration values each corresponding to aphysical area on a display.
 21. The image data processing method asclaimed in claim 20, further comprising receiving the calibrationinformation to store the calibration information in correspondingaddresses in the storage unit.
 22. The image data processing method asclaimed in claim 20, further comprising: outputting a gamma-calibratedimage data according to the calibrated image data; and outputting one ofthe gamma-calibrated image data and the calibrated image data.
 23. Theimage data processing method as claimed in claim 20, wherein thecorresponding calibration value has a spatial correspondence with a dot,a pixel, a row, a column, or a predetermined section.